Communicating programming practice with screencasts

One of the things that I have struggled with over the years is how to teach people how to actually program -- by this I mean the minute-to-minute process and techniques of generating code, more so than syntax and data structures and algorithms. This is generally not taught explicitly in college: most undergraduate students pick it up in the process of doing homeworks, by working with other people, observing TAs, and evolving their own practice. Most science graduate students never take a formal course in programming or software development, as far as I can tell, so they pick it up haphazardly from their colleagues. Open source hackers may get their practice from sprints, but usually by the time you get to a sprint you are already wedged fairly far into your own set of habits.

Despite this lack of explicit teaching, I think it's clear that programming practice is really important. I and the other Linux/UNIX geeks I know all have a fairly small set of basic approaches -- command-line driven, mostly emacs or vi, with lots of automation at the shell -- that we apply to all of our problems, and it is all pretty optimized for the tools and tasks we have. I would be hard pressed to imagine a significantly more efficient and effective set of practices (which just tells me that there is probably something much better, but it's far away from my current practices :).

Now that I'm a professional educator, I'd like to teach this, because what I see students doing is so darned inefficient by comparison. I regularly watch students struggle with the mouse to switch between windows, copy and paste by selecting or dragging, and otherwise completely fail to make use of keyboard shortcuts. I see a lot of code being built from scratch by guess-work, without lots of Google-fu or copy/pasting and editing. Version control isn't integrated into their minute-by-minute process. Testing? Hah. We don't even teach automated testing here at MSU. It's an understatement to say that using all of these techniques together is a conceptual leap that many students seem ill-prepared to make.

Last term I co-taught an intro graduate course in computation for evolutionary biologists using IPython Notebook running in the cloud, and I made extensive use of screencasts as a way to show the students how I worked and how I thought. It went pretty well -- several students told me that they really appreciated being able to see what I was doing and hear why I was doing it, and being able to pause and rewind was very helpful when they ran into trouble.

So this term, for my database-backed Web development course, I decided to post videos of the homework solutions for the second homework, which is part of a whole-term class project to build a distributed peer-to-peer liquor cabinet and party planning Web site. (Hey, you gotta teach 'em somehow, right?)

I posted the example solutions as a github branch as well as videos showing me solving each of the sub problems in real time, with discussion:

HW 2.1 --

HW 2.2 --

HW 2.3 --

HW 2.4 --

HW 2.5 --

HW 2.6 --

I think the videos are decent screencasts, and by breaking them down this way I made it possible for students to look only at the section they had questions about. Each screencasts is 5-10 minutes total, and now I can use them for other classes, too.

So far so good, and I doubt many students have spent much time looking at them, but maybe some will. We'll have to see if my contentment in having produced them matches their actual utility in the class :).

But then something entertaining happened. Greg Wilson is always bugging us (where "us" means pretty much anyone whose e-mail inbox he has access to) about developing hands-on examples that we can use in Software Carpentry, so I sent these videos to the SWC 'tutors' mailing list with a note that I'd love help writing better homeworks. And within an hour or so, I got back two nice polite e-mails from other members of the list, offering better solutions. One was about HW 2.1 --

It might be safer to .lstrip() the line before checking for comments (to allow indented comments). Also, not line[0].strip() doesn't test for lines with only white space. it tests for lines that have white space as the first character. 'not line.strip()[0]' would be all white space... That would also make 'not line' redundant.

I also got a more general offer from someone else to peer review my homework solutions, and chastising me for using

fp = open(filename)
  ... do stuff ...

instead of

with open(filename) as fp:
   ... do stuff


I find this little episode very entertaining. I love the notion that other people (at least one is another professor) had the spare time to watch the videos and then critique what I'd done and then send me the critique; I also like the point that the quest for perfect code is ongoing. I am particularly entertained by the fact that they are both right, and that my explanation of my code was in some cases facile, shallow, and somewhat wrong (although not significantly enough to make me redo the videos -- the perfect is the enemy of the good enough!)

And, finally, although no feedback spoke directly to this, I am in love with the notion that we can convey effective practice through video. I think this episode is a great indication that if we could get students to record themselves working through problems, we could learn how they are responding to our instruction and start to develop a deeper understanding of the traps for the novice that lie within our current programming processes.


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